Fix the link of Django logging directive
Fix the link of Django logging directive

Current link is out of date. It's 404 Page not found now.
Change it to an address regardless of specific django version.

Remove the warning content since the bug has been fixed.

Change-Id: Idd0060313d538e25f9b89d7197adca739d2f6782
Closes-Bug: #1560449

noironetworks/horizon,yeming233/horizon,wolverineav/horizon,noironetworks/horizon,ChameleonCloud/horizon,openstack/horizon,NeCTAR-RC/horizon,BiznetGIO/horizon,bigswitch/horizon,bac/horizon,sandvine/horizon,coreycb/horizon,noironetworks/horizon,openstack/horizon,Mirantis/mos-horizon,bac/horizon,BiznetGIO/horizon,Mirantis/mos-horizon,ChameleonCloud/horizon,sandvine/horizon,wolverineav/horizon,openstack/horizon,yeming233/horizon,NeCTAR-RC/horizon,bigswitch/horizon,Mirantis/mos-horizon,NeCTAR-RC/horizon,bac/horizon,NeCTAR-RC/horizon,bac/horizon,yeming233/horizon,BiznetGIO/horizon,coreycb/horizon,sandvine/horizon,sandvine/horizon,noironetworks/horizon,wolverineav/horizon,wolverineav/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,yeming233/horizon,coreycb/horizon,Mirantis/mos-horizon,bigswitch/horizon,BiznetGIO/horizon,bigswitch/horizon,coreycb/horizon,openstack/horizon